This invention relates to a method and an apparatus for making electrical connections between electrical components in a plastic mold and to a plastic molding press and to components used in such an apparatus.
Currently plastic injection molds are provided with an increasing number of electrical components disposed within the mold and which have various wires or leads connected thereto. These wires extend from the exterior of the mold and are for connection to a press or to a power source. Typically, some of the wires which are connected to the power source are used to supply electrical power for heaters such as used in a hot runner system or for heated sprues within the mold. A number of wires are connected to internal sensors having electrical switches which assure the positioning of the molding plates, cores or ejectors. Additionally, there are often cavity pressure switches which monitor the pressure within the cavity either of the moving mold half or the stationary mold half, or both. Often the switches are used to monitor the position of whether the mold is closed and whether or not there is a proper temperature at the mold or at various locations such as the sprue. Typically thermocouples are positioned within the mold to monitor temperature and electrical leads extend from the thermocouples outwardly of the mold. A problem with many molds today is that there is a risk of damaging lose wire when transporting the mold.
A mold maker makes many different molds, and many of the molds have a different assortment of electrical components therein. Some molds will have hot sprue bushings, hot runners and others will not. Some molds may have core limit switches which sense the positioning of the core while others do not have any such switches or cores. Also, the ejectors may have switches to show that the part ejection has taken place properly while other molds do not sense ejection.
The mold maker buys electrical components from various manufacturers and installs them in the mold in accordance with the particular specifications for any given mold. The terms used by different press manufacturers or different mold makers vary from one instance to another instance for the same type of component or the same type of sensor. There is no commonality as to terms used for the various particular sensors or heaters such that different presses will have different leads for connection labelled different than other press manufacturers to the same mold. Thus, depending where the mold is used, the person installing the mold will have to understand the various terms used for the electrical components as well as different terms which may be used by the press manufacturer. The various electrical components including switches and sensors are not specifically designed or built for easy installation into the mold.
The mold maker generally is under considerable time constraints to deliver the mold to the customer. Typically, a six to eight-week period is required for the making and delivery of a mold. Under such time constraints, the mold maker has little time or interest in a lack of uniformity of positions or names of any other electrical components that are in the mold.
At the other end, the mold press manufacturers each manufactures a press which is controlled in a different manner. Also, the same manufacturer will provide different presses to perform different functions such as runnerless molding, hot sprue bushing type of molding or various other types of molding. Most of the plastic molding presses have a computerized or programmable logic control system which operates the press. Often there is an interface with a process monitoring system that allows a monitoring of the injection molding press and mold with respect to operation and operating parameters. The common process system connects molding presses to a common computer which provides the data with respect to the operation of the molds and these presses. Many of the molds has a different operating sequence; and particularly, where they have different electrical components, there will be different inputs for a particular given mold. There is a need to identify the mold to make sure that the particular operating sequence is appropriate for the mold that is being placed in the press.
Upon delivery of a mold from the mold maker to the injection molding plant, the electrical leads are typically dangling from the sides of the mold. The dangling wires are often pinched, broken or sometimes pulled from the electrical component, thereby disabling the internal electrical component. There is a considerable expense involved in removing a disabled component from the mold. The cost of disassembling and reassembling the mold for the installation of a replacement component for that which was damaged because of the pulling of the dangling lead is an expensive proposition. In this situation, there is often a time constraint in that a very skilled person must be found with the know- how to assembly and disassemble molds.
Also, skilled personnel are required to connect the electrical leads from a mold to the press. The person who does this rigging or connection must know how the mold operates because the wires that are dangling therefrom need to be connected to the press, and he should know which wires are sensing what function in the mold. The skilled person usually must be able to connect a mold to each of several different presses made by different manufacturers because often, the same injection molding plant will have several kinds of presses. Also, the terms used for the different sensors are often varied from one press manufacturer to another press manufacturer, as likewise the components installed by a mold maker may be termed different from one mold manufacturer to the next mold manufacturer. It sometimes occurs that an incorrect connection is made--for example, a power lead may be connected to a thermocouple, it will destroy the thermocouple by electrically overloading the thermocouple. Sometimes, the PLC controller becomes damaged. A need exists for a system to simplify the mold set-up of electrical components.
Thus, there is a need for a new and improved system for connecting electrical components in an injection mold to various injection molding presses.